<!DOCTYPE html>
<html>
<head>
<style>
#list {
    width: 639px;
}
.item {
  width: 256px;
  margin: 8px auto;
}
.icon {
  display: block;
  width: 256px;
  height: 256px;
  border: 1px solid red;
  background-color: red;
}
#layer {
  position: relative;
  top: -258px;
  width: 256px;
  height: 256px;
  background: green;
  border: 1px solid black;
}
</style>
</head>
<body>
<div id="list">
    <div class="item"><img class="icon" style="transform: scaleX(-1);">
      <div id="layer"></div>
    </div>
</div>
</body>